4^4 
Journal of Agricultural Research 
Vol. VIII, No. n 
to a colony. These are given at the rate of 3 a day for 10 days. By 
this procedure the cultures at the last, or tenth inoculation, are 10 days 
older than those at the first inoculation, assuming that the three slopes 
were always given on every consecutive day without a break. The age 
of cultures at the first inoculation varies considerably, ranging from 1 
day to 16 days. Sometimes the interval between inoculations for one or 
more times is greater than a day, thus advancing the age of the culture 
at the last inoculation considerably. Only one colony was inoculated 
with a fresh 24-hour-old culture at each feeding, since it was found that 
most cultures do not produce spores in abundance until somewhat older. 
Fig. 4.— Bacillus alvei: Smear from a 48-hour-old agar culture. X 1,480. Note the vestige of rod clinging to 
nearly all of the spores. Note also the tendency of the spores to occur in rows. 
While 3 slopes for io days was the usual allotment of a colony under 
inoculation, this was varied at times so that some colonies received a 
somewhat less number than 30 agar slopes of culture. 
The cultures were inoculated by feeding to the bees in sterile sirup, 
washing the culture off of the slopes with sterile physiological salt solution 
by the use of a sterile glass rod. The cultures were fed when the organ¬ 
isms were forming spores in abundance. 
DISCUSSION OF INOCULATIONS 
Table I gives various data as to the number of colonies inoculated, 
kinds of media used, number of different strains, number of different 
